Abstract: In order to create a rotary kiln burner particularly for fine-grained solid fuels such as coal dust, with jet air nozzles which can be adjusted easily and effectively during operation of the kiln in order to change the divergence angle of the high-speed jet air streams to change the flame shape and optimise the combustion, the invention proposes attaching the jet air nozzles (20) with the nozzle openings divergent to the burner axis at the end of jet air pipes (21), and arranging these around the burner axis, with the axes parallel, with the jet air pipes (21) arranged inside an annular cooling air space (22) surrounding the coal dust channel (16) and enclosed on the outside by the burner housing pipe (19), mounted so that they can rotate around the jet air pipe axes, so that on turning the jet air pipes (21) at the cold end of the burner lance, the divergence of the high-speed jet air streams, and thus the angle of the jet air flow cone in relation to the coal dust cone can be changed and adjusted.